Identification Properties
• STREAK
– Color of its powder
– Does not change
– Metallic: as dark as
sample
– Nonmetallic: white to
colorless
Streak Plate
Identification Properties
• CLEAVAGE
– Tendency to split easily
or break along flat
surfaces
– Mica – 1 direction
• FRACTURE
– Break on uneven
surfaces
– Conchoidal - obsidian
Identification Properties
• HARDNESS
– Resistance to being
scratched
– Mohs’ Scale of
Hardness
Hardness:
resistance of
a mineral to
abrasion
scratching
Mohs’ Scale of
Hardness
Special Identification Properties
• Magnetism
Magnetite
Rocks and the Rock Cycle
“The present is the key to the past”
• Geologic processes that happen today
happened in the past
• Earth’s present physical features were
formed by these processes
Igneous Rocks
• Formed by cooling and
hardening of magma
• Plutonic –
intrusive
, forms
underground
• Volcanic –
extrusive
, forms
on surface
• 2 kinds of magma
High SiO2%, light colored,
thick, slow moving called
acidic
Low SiO2%, dark colored
called mafic
Sedimentary Rock
• Form from sediments
hardening into rock
• From pieces of other rocks
clastic
, sandstone, shale
• Precipitating out of a
solution
chemical
,
limestone, rock salt
• From remains of plants and
animals
organic
, coal,
limestone
Metamorphic Rock
• “Changed” by heat and pressure
– mountain building
– Contact with magma
Weathering and the
formation of
sedimentary rocks
Prof. Dr. Ziad Abu-Hamatteh
Faculty of Engineering Technology
Al-Balqa Applied University
Civil Engineering Department
Weathering and the formation
of sedimentary rocks
• All materials are susceptible to weathering = interaction between
materials and weather!
• Synthetic and natural materials (concrete + minerals and rocks,
iron rods etc.)
• Minerals and rocks that form at high P and T (below or above
Earth’s Surface) are unstable on the Surface of the Earth.
• They change until they achieve equilibrium with the new
conditions.
• Weathering processes are broadly divided into mechanical and
chemical weathering.
Place of Formation
Temperature
cold
hot
shallow
deep
metamorphic
igneous
sedimentary
700 C
30 miles
P
r
e
s
s
u
r
e
Sedimentary rock forming processes
W
T
D
L
